Mean-Field Analysis for Learning Subspace-Sparse Polynomials with Gaussian Input

Ziang Chen; Rong Ge

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arXiv · 2402.08948

Mean-Field Analysis for Learning Subspace-Sparse Polynomials with Gaussian Input

Ziang Chen·Rong Ge

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Abstract

In this work, we study the mean-field flow for learning subspace-sparse polynomials using stochastic gradient descent and two-layer neural networks, where the input distribution is standard Gaussian and the output only depends on the projection of the input onto a low-dimensional subspace. We establish a necessary condition for SGD-learnability, involving both the characteristics of the target function and the expressiveness of the activation function. In addition, we prove that the condition is almost sufficient, in the sense that a condition slightly stronger than the necessary condition can guarantee the exponential decay of the loss functional to zero.

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Ziang Chen, Rong Ge. 2024-02-14. Mean-Field Analysis for Learning Subspace-Sparse Polynomials with Gaussian Input. https://arxiv.org/abs/2402.08948

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